The present invention relates to a map retrieving system applicable to business of displaying maps, etc. in accordance with an inputted address (business of replying to inquiries such as road guidance etc.) and in particular to a map retrieving system capable of searching and displaying maps with a high efficiency by learning maps already utilized.
Heretofore, as a map retrieving system, as described, e.g., in JP-A-1-287594, there is known a system having a function of displaying a relevant map by a one-touch operation, in which when a "local area number" (number assigned to ken or state.fwdarw.shi.fwdarw.cho) (ken, shi and cho mean prefecture, city and town in English, respectively), a house number, a street number, etc. are inputted, maps of the relevant local area and place names are displayed one after another, and the order of display of maps or road maps to destinations used repeatedly is registered.
The prior art technique described above has a "function of inputting previously the order of display of maps", by which maps on a route to an intended destination are displayed one after another according to an itinerary. This is a system useful, e.g., for an autoroute electronic atlas, when a user, who knows all necessary items up to the name of cho and the house number of the position at present and the destination position, utilizes it to refer thereto up to the destination and to display corresponding maps. However a system, in which the order of display of a series of maps is registered and determined, as described above, is not suitable for an answering system used in a guiding station, which should answer inquires from those (e.g., passengers) who know only vaguely their positions at present and destination positions (for the purpose of confirming precisely these positions up to their house numbers). Such an inquiry answering system can be used apart therefrom in the case where a passenger informs a fire station concerned of a fire, which he has found incidentally in a local area, with which he is unfamiliar, etc. In this case, the passenger does not know as far as the house number. Therefore he makes inquiries at a guiding station, an office concerned, etc. about or informs them of a name of cho or names of constructions, which can be marks, such as a building, an advertising board, etc. on the basis of a situation, where he is at present. It can be thought that the guiding station displays suitably several sectional maps of the cho having the relevant name (it is supposed, e.g., that a local area having a name of cho is divided into a plurality of meshes in display image unit) with this due and that it identifies a precise place, where the passenger is, by looking for a target building or mark (of which the passenger talks) therefrom, and informs him thereof. Consequently, for this kind of guiding and answering system it is desirable that it can display at random a plurality of maps (sectional maps) relating to a specified address (name of local area such as a name of cho) and that a map (sectional map), in which the destination is written, is found as soon as possible to be displayed.
However, as the prior art technique described above, no attention is paid to the fact that the order of displays being determined previously, related maps are searched at random, responding to the content of the inquiry from a person who makes inquiries, so as to display a target map in a short time with a high efficiency.
Therefore, the inventors of the present invention have thought as a result of various studies that if this kind of map systems have a learning function and can presuppose to some degree sectional maps necessary for answering an inquiry at that time, e.g., on the basis of data answering inquiries up to that time, it is possible to display rapidly a required sectional map with a high efficiency by selecting it from sectional maps having a high presupposed probability to display it.